In order to make available conveying systems with a two-dimensional or three-dimensional configuration, diverting stations are required for conveying tracks which are otherwise arranged linearly. A common way of bringing about diverting stations is to provide an ingoing and an outgoing linear conveying track, which tracks are partly superimposed within the diverting area. When goods are conveyed along the conveying track, the goods are transferred from the ingoing linear conveying track to the outgoing linear conveying track. In order to bring about the said transfer, it is usually necessary to ensure, by raising or lowering one of the tracks, that the propelling of the goods is transferred from the ingoing to the outgoing linear track. With this type of diverting station, it is difficult to bring about continuous operation through the diverting station, which means that the diverting station can be limiting for the average track speed. Furthermore, in this type of diverting station, use is made of quite a number of active components, which makes this type of diverting station expensive to manufacture. Often included are inter alia motorized lifting units, sensors for monitoring the position of the goods in the diverting station and a control unit for correct control of the conveying track and lifting units depending on the position of the goods in the diverting station.
In order to overcome the abovementioned problems, use is therefore made of curve units comprising a curved guide element for diverting a chain conveying track from an ingoing direction to an outgoing direction which is angled in relation to the said ingoing direction. One way of producing curve units is to use curve elements made from a metal sheet which has been bent into the desired track shape and on which a support flange is firmly welded. The function of the support flange is to constitute a guide rail for a first side of chain elements forming part of the chain conveying track. The curve element is then assembled to form a curve unit by using a second curve element which has a support surface intended to constitute a guide rail for a second side of chain elements forming part of the chain conveying track. The second curve element can be designed in the same way as the first curve element with a mirror-inverted position of the welded-on flange. Alternatively, the second bend element can consist of a rotatably arranged turntable, the periphery of which is arranged so as to constitute a guide rail for one side of a chain in the bend unit. A first disadvantage of this type of bend unit is that extensive welding work is necessary for preparation of the bend unit. Apart from the fact that the welding itself is time-consuming, the weld joint gives rise to pores in the weld metal. In the event that the bend unit is to be used in installations with a high cleanliness requirement, for example in the food industry, the presence of pores can give rise to difficulties in cleaning the apparatus, with the risk of bacteria as a consequence. In order to reduce this risk, the weld joints are usually polished to eliminate the pores. This process step is also time-consuming and therefore makes the end product more expensive.
Another known way of manufacturing bend units is described implicitly by FR 2741053, in which a bend unit with a curved guide track made of plastic is used. A possible manufacturing method is injection moulding or extrusion or alternatively moulding of the track.
Furthermore, a bend unit which has a backbone-shaped guide track which is constructed around a web on which vertebra-shaped projections are formed is described in FR 26 74 513. The guide track is manufactured by moulding plastic in one piece, or alternatively plastic projections being mounted on a web made of metal. This bend unit and other previously known bend units have the disadvantages that they are complicated to manufacture and that delivery has to take place in the assembled state, which can take up a great deal of space.